Does Warmer Mean Savings for Data Centers?

Data centers continue to come under scrutiny for the level of energy they use. That only makes sense, because these huge data centers need to continue running the air conditioning to keep the machines cool, right?

Researchers at University of Toronto Scarborough (UTSC) say in a research paper it is possible to turn down the air conditioning. But energy experts in the trenches say the answer is not that simple and a thorough analysis will always have to be done.

As data centers continue to grow, they have required more energy, accounting for about 1.5 percent of global electricity usage. A large part of that is the cooling necessary to keep the machinery functioning properly.

In a paper entitled “Temperature Management in Data Centers: Why Some (Might) Like It Hot,” UTSC research team found warmer temperatures than are normally recommended might be able to save energy without negatively having an impact on equipment reliability and longevity.

Data centers typically operate at temperatures from 68F to 72F (20C to 22C). Estimates from the study show that just 1 degree increase in temperature could save 2 to 5 percent of the energy the centers consume. While that is just one degree difference, researchers said most data centers could probably increase temperatures much more than that.

When it comes to data centers, however, it is not as simple as allowing the temperature to rise.

“For some Industries, this is like saying you will save money by turning off the bathroom light,” said Michael Mackenzie, vice president, Energy Management Transformation at Schneider Electric. “For many large industrial customers, most of the energy consumed comes directly from the machines, pumps, and process heating or cooling so savings from an HVAC system will represent less of an impact.”

Jim Parker, senior consulting engineer for energy efficiency at Schneider Electric agrees increasing the temperature may not do much.

“That probably won’t save a whole lot,” he said. “It will save some, but not as much as you would think.”

Instead, he said, real energy cost savings for data centers can come in two different directions, bringing in fresh outside air to cool off equipment or use water cooling.

Both areas have issues, he said, but they can also reduce energy costs because “the data center industry is taking energy seriously.”

Allowing fresh air in from outside would work nicely, Parker said, but it does have a security issue of air contamination coming into the building. Even though the air can be filtered, “How do you convince users to take the risk?” Parker asked.

He also mentioned water cooling the chips, which he said will work, but that is a decision that has to be made at the design level.”

As far as the University of Toronto study goes, the researchers collected data from data centers run by Google, Los Alamos National Labs, and others. They also directly tested the effect of temperature on equipment performance in their lab. Their data showed that higher temperatures either weren’t associated with negative effects on the equipment, or else the negative effects were smaller than predicted.

Energy issues will continue to be a huge issue for data centers moving forward.

In one study, Jonathan G. Koomey, a consulting professor in the civil and environmental engineering department atStanfordUniversityfound electricity used by data centers worldwide grew 56 percent from 2005 to 2010. In theUnited States, power consumption increased by 36 percent over that time frame, according to Koomey’s report entitled “Growth in Data Center Power Use 2005 to 2010.”

Electricity used in global data centers accounted for between 1.1 percent and 1.5 percent of total electricity use, respectively. For theU.S., that number was a bit higher between 1.7 percent and 2.2 percent, according to the report.